In recent years, a stepping motor achieving smooth rotations without unevenness and thereby being capable of exhibiting low vibration and low noise is often used in electronic equipment such as a printer, a facsimile machine, a scanner, or the like. The stepping motor is generally driven by applying an excitation current to a two-phase excitation coil while allowing the excitation current having phases shifted one another by 90° degrees to be changed into a waveform close to a sine wave (in other words, pseudo sine wave).
Japanese Patent Laying-Open No. 2008-029145 (PTD 1) discloses an example of a drive circuit of a stepping motor. The drive circuit includes a target voltage generating unit for generating a target voltage indicating a target value of an excitation current based on a reference voltage indicating an upper limit of the excitation current, and a current controller for controlling the excitation current based on the target voltage.